This invention relates generally to fluid dispensing systems and, more particularly, to an improved cartridge type control valve for use in the dispensing head for such systems.
In U.S. Pat. No. 3,980,273 a cartridge type control valve includes inlet duct means formed in an inverted J-shaped configuration. The inlet duct means is formed by a longitudinal leg portion fabricated integrally with the cup-like means which defines the fluid transfer chamber in the control valve and an independent transverse leg ultrasonically welded at one end to the longitudinal leg and to the side wall of the cup-like member so that it is cantilevered into the center section of the fluid transfer chamber. The transverse leg at its free end has a downwardly disposed outlet port about which is formed a valve seat. Disposed in operative association with the outlet port and disposed for reciprocal movement towards and away from the valve seat is a valve head movable from a normally closed position of the control valve to an open position and vice versa by a manually operated actuating means.
In the above mentioned construction the valve head is spring biased against the valve seat on the free end of the transverse leg to normally maintain the control valve closed such that a moment of force is continuously exerted about the point where the transverse leg and longitudinal leg of the inlet duct are ultrasonically welded. As a result there is a tendancy to produce cracks or breakage in this construction at this point which causes leakage and/or failure of the control valve.
Other patents such as U.S. Pat. Nos. 3,033,466, 1,926,069; 868,599, and 632,808 disclose control valves having inverted J-shaped or L-shaped inlet duct members for use in such systems, in which the inlet duct members are formed from integral tubular elements.
With many of these valves, the J-shaped or L-shaped tubular inlet duct member is connected with insufficient reenforcing means for the portion extending into the fluid transfer chamber formed in the control valve. Such placement may result in leakage of fluid from the outlet port of the tubular inlet duct members. This is particularly true in view of the moment of force transmitted to the free end of the tubular inlet duct members due to engagement of the valve head with the valve seat about the outlet port end of such inlet duct members because of the tendancy of the free end of the tubular inlet duct members to misalign under such forces.
Deformation of the tubular inlet duct member can result, not only from the forces of the valve head against the seat, but also, initially, by those forces to which the control valve is exposed when it is installed in the dispensing head by means of the threaded retaining ring. When the cartridge type control valve is clamped against the base of the cavity in the dispensing head, the tendency is for the center of the cup-like member of the control valve to be crowned in a direction toward the operating end of the control valve. This is due to the fact that the outer walls of the cup-like member are relatively stiff, but the material toward the center of the bottom of the cup-like member is free to deflect in an upward direction due to the hydraulic forces of the gasket positioned between the bottom of the cup-like member and the cavity in the dispensing head. Since the inlet duct is secured to the bottom of the cup-like member at a position somewhat inwardly from the outer edges thereof, there is a tendency for the vertical centerline of the tubular inlet duct member to be displaced out of parallel from the centerline of the cup-like member and the cavity in the dispensing head.
This is illustrated in U.S. Pat. No. 632,808 where an inverted generally J-shaped tubular member is connected in the housing with one end in communication with the source of fluid to be controlled. The inlet duct member is bent or shaped for engagement or contact with the side wall of the housing. However, because the inverted J-shaped tubular member is at best connected in assembled position in the housing, merely for continuous communication with the source of fluid to be controlled, it suffers from the same problems of misalignment and/or deformation particularly because of its bent configuration to bring it into abutment with the side wall. Such distortion or bending of the inverted J-shaped inlet duct member makes it, difficult to position in the housing for communicating with the source of fluid to be controlled, and there is no means to avoid leakage and/or failure problems caused by the action between the valve head and the free end of the transverse portion of the inverted J-shaped inlet duct which contains the outlet port for the fluid to be controlled.
The present invention seeks to overcome these problems of the prior art and to provide an improved cartridge type control valve having an integral tubular J-shaped inlet duct member which is staked in the cup-like member of the control valve defining the fluid transfer chamber in inverted position therein. In assembled position the outlet port end of the inverted J-shaped inlet duct member is disposed in the fluid transfer chamber in the longitudinal line of the control valve for operative alignment and coaction with the valve means for opening and closing the outlet port and further means is provided to reenforce the inverted J-shaped inlet duct member in this assembled position so as to prevent misalignment thereof under the static and dynamic operating and installation conditions of the control valve.